diff -r 000000000000 -r 6474c204b198 layout/base/nsIFrameTraversal.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/base/nsIFrameTraversal.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef NSIFRAMETRAVERSAL_H
+#define NSIFRAMETRAVERSAL_H
+
+#include "nsISupports.h"
+#include "nsIFrame.h"
+
+#define NS_IFRAMEENUMERATOR_IID \
+{ 0x7c633f5d, 0x91eb, 0x494e, \
+  { 0xa1, 0x40, 0x17, 0x46, 0x17, 0x4c, 0x23, 0xd3 } }
+
+class nsIFrameEnumerator : public nsISupports
+{
+public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IFRAMEENUMERATOR_IID)
+
+  virtual void First() = 0;
+  virtual void Next() = 0;
+  virtual nsIFrame* CurrentItem() = 0;
+  virtual bool IsDone() = 0;
+
+  virtual void Last() = 0;
+  virtual void Prev() = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIFrameEnumerator, NS_IFRAMEENUMERATOR_IID)
+
+enum nsIteratorType {
+  eLeaf,
+  ePreOrder,
+  ePostOrder
+};
+
+// {9d469828-9bf2-4151-a385-05f30219221b}
+#define NS_IFRAMETRAVERSAL_IID \
+{ 0x9d469828, 0x9bf2, 0x4151, { 0xa3, 0x85, 0x05, 0xf3, 0x02, 0x19, 0x22, 0x1b } }
+
+class nsIFrameTraversal : public nsISupports
+{
+public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IFRAMETRAVERSAL_IID)
+
+  /**
+   * Create a frame iterator with the specified properties.
+   * @param aEnumerator [out] the created iterator
+   * @param aPresContext [in]
+   * @param aStart [in] the frame to start iterating from
+   * @param aType [in] the type of the iterator: leaf, pre-order, or post-order
+   * @param aVisual [in] whether the iterator should traverse frames in visual
+   *        bidi order
+   * @param aLockInScrollView [in] whether to stop iterating when exiting a
+   *        scroll view
+   * @param aFollowOOFs [in] whether the iterator should follow out-of-flows.
+   *        If true, when reaching a placeholder frame while going down will get
+   *        the real frame. Going back up will go on past the placeholder,
+   *        so the placeholders are logically part of the frame tree.
+   */
+  NS_IMETHOD NewFrameTraversal(nsIFrameEnumerator **aEnumerator,
+                               nsPresContext* aPresContext,
+                               nsIFrame *aStart,
+                               int32_t aType,
+                               bool aVisual,
+                               bool aLockInScrollView,
+                               bool aFollowOOFs) = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsIFrameTraversal, NS_IFRAMETRAVERSAL_IID)
+
+#endif //NSIFRAMETRAVERSAL_H